Exceptional Events

The purpose of the exceptional events rule is to ensure that regulatory decisions under the Clean Air Act are not biased by monitored air quality data over which a state has little or no control.

Exceptional Event App for Creating Demonstrations

WESTAR/WRAP is coordinating an effort lead by staff at the South Coast Air Quality Management District (SCAQMD) to develop an online app to assist air agencies in preparing an Exceptional Events (EE) Demonstration for submission to the EPA. This interactive app lays the ground work for automating much of the technical data collection required in Exceptional Event Demonstrations. The online tool is a collaborative project among air quality regulatory agencies across the Nation. It is, and will continue to be, a work in progress. If you are interested in contributing to this project, please contact Rhonda Payne at WESTAR or Jay Baker at WESTAR.

• April 2025 EE app training recording.
• A demonstration of the app from a MARAMA webinar can be viewed here.

While use of this app in no way guarantees EPA concurrence for any EE demo submitted to the EPA, we are working with them to make sure the outputs meet the requirements of the EE rule. EE demos created using this app will be subject to the same review process as EE demos that do not use this app.

Thank you to all those who helped organize, present, host, and attend the National Exceptional Events Workshop. All of the meeting presentations and recordings are posted here for you to review and learn.

EPA September 2016 Final Rule and Guidance

• EPA’s Exceptional Events Rule and Guidance